The present invention generally relates to the treatment of a substrate surface. Surface treatment, for example oxidizing, cleaning, or planarizing a substrate surface, is a critical operation, especially in the semiconductor industry, where irregularities within a surface or foreign contaminants on the surface can cause device failure. The sensitivity to foreign matter on the surface and to irregularities within the surface is increased as device sizes shrink in the semiconductor industry. Foreign matter as small as sub-micron particles can destroy a semiconductor integrated circuit. Furthermore, when a surface treatment is being carried out, it is desirable that the treatment does not otherwise damage the substrate surface being treated.
An example of foreign matter which commonly must be removed from a surface in the semiconductor industry is organic material. Photoresist is an example of an organic material frequently used in the semiconductor processing industry. After a photoresist film has been used to create a mask on a semiconductor surface being processed, it is generally necessary that the photoresist film be completely removed before subsequent fabrication processes may be carried out. The complete removal of the photoresist film is made more difficult when the photoresist film becomes hardened on the substrate surface. Hardening of the photoresist film occurs when the photoresist film is exposed to a plasma environment or ion implantation, two common fabrication processes. Incompletely removed photoresist can cause device failures.
It is commonly known that organic contaminants may be removed by ultraviolet (uv) cleaning. Ultraviolet light, which is defined by the wavelength range of 4 nm to 380 nm, has been known to decompose organic molecules. Another method known in the art which is useful for removing or assisting in the removal of unwanted organic material is the chemical oxidation of these organics.
Processes and apparatus for using uv light to decompose organic molecules and treat a substrate surface are known in the related art. The related art also provides a method for the generation of ozone for use in surface treatment. The production of ozone from high voltage discharges between metal electrodes, however, frequently produces metal ion contaminants unsuitable for the semiconductor processing industry. A further shortcoming of the prior art is that separate sources of energy are required for ozone production and uv light surface treatment.